Bobbin case for sewing machines

ABSTRACT

The invention relates to an improvement of a bobbin case in which a finger piece on the bobbin case can be maintained in raised position to facilitate grasping of the finger piece to thereby ease the fitting and unfitting operations of the bobbin case through the narrow opening in the machine and to further accomplish this purpose with a simple construction of the bobbin case.

United States Patent Kasawaki 151 3,682,121 [4 1 Aug. 8, 1972 541 BOBBINI CASE FOR SEWING MACHINES [72] Inventor: Keiki Kasawaki, Tokyo, Japan [73] Assignee: Kenji Watanabe, Nugata-ken, Japan [22] Filed: June 9, 1970 [21] Appl. No.: 44,723

[30] Foreign Application Priority Data June 9, 1969 Japan ..44/44614 July 22, 1969 Japan ..44/57395 June 3, 1970 Japan ..45/47209 June 3, 1970 Japan ..45/47210 US. Cl ..l12/23l Field of Search ..l 12/231, 228

[56] References Cited UNITED STATES PATENTS 1,995,278 3/1935 Kessler ..1 12/228 2,154,403 4/1939 Karle ..112/231 2,949,874 8/1960 Kuhar ..112/231 3,347,193 10/1967 Perri ..1 12/228 Primary Examiner-Alfred R. Guest Attorney-Michael S. Striker [57] ABSTRACT The invention relates to an improvement of a bobbin case in which a finger piece on the bobbin case can be maintained in raised position to facilitate grasping of the finger piece to thereby ease the fitting and unfitting operations of the bobbin case through the narrow opening in the machine and to further accomplish this purpose with a simple construction of the bobbin case.

6 Clains, 16 Drawing Figures n- Illl'llllln PATENTEDAUB 8 m 3,682,121

SHEET 2 0F 5 INVENTOR 11am 114M944" v ATTORNEY PA'TENTEDMIB W Y $582,121 SHEEI 3 BF 6 INVENTOR ken klfl l/JL BY A1011 f/n'l ATTORNEY PATENTED 8 I972 3.682.121

SHEET 0F 6 1 BOBBIN CASE FOR SEWING MACHINES DETAILED EXPLANATION The invention relates to of a bobbin case for sewing machines, constructed to facilitate the fitting and of the same. operation with the simple structure.

The bobbin for the home sewing machine is generally 20mm in diameter and accordingly the bobbin case to furnish it therein is around 21 to 21.5 mm in diameter, and it is fitted to the bobbin shaft of the rotary shuttle. Such a bobbin case has a sliding member on its front part, on which a spring acts However in the known constructions the finger piece turnably mounted on the sliding member is always leveled by the action of the spring, and since this bobbin case is a small member which is provided under the needle plate of the bed, it is not easy to engage and release the bobbin case with the finger piece. That is, said finger piece is provided on the front side of the bobbin case, besides it must be moved not to hook a thread on the bobbin case so that it will be around 7 mm in width and 15 mm in length, and as the finger piece is pivoted with one side on said sliding member (bobbin case), it is fairly diflicult to pick up the finger piece of such a bobbin case with the operators fingers out of the hole (around X 5 cm in the ordinal home sewing machine). In addition, the finger piece can be held in raised position only by fingers.

In this construction, the sliding piece has a stopping screw to necessarily limit its movement. Without this means, when the said finger piece is turned through an angle greater than 90, in the condition of no bobbin this finger piece is freely rotated, and when the finger piece is leveled over 90 the engagement of a cam and the bobbin case is released and the finger piece is rotated 180 so that the sliding member and the finger piece slip out of the bobbin case under the action of the spring. Therefore it is indispensable in the prior art bobbin case to equip the sliding member with a stopping screw. As the bobbin case is small, it is not easy to screw this stopper within the bobbin case. The production is also intricate since it is necessary to prepare a special screw and make a screwing hole in the sliding piece. If the relative position between the cam of the finger piece and this stopping screw is not exactly obtained due to a slight manufacturing error, the standing angle of the finger piece is too small or exceeds 90 so that the engagement of the cam and the bobbin case cannot be provided, and it is rather difficult to position such a stopping screw at the precise portion which causes bad products. I

The invention aims to remove the above said troublesome disadvantages in conventional construction. A principal object is to maintain the finger piece when turned by the operator to the raised position, in this raised position, and whereafter the finger operation to keep this condition is not required. The thus raised finger piece may be used as an advantageous picking portion for fitting and unfitting operation. The operator only pays attention to the raised piece and it is unnecessary to pay any attention to maintaining the standing condition. Further, when the gripped portion occasionally slips out of the fingers the piece keeps standing. In this manner, the operator can easily engage a bobbin case and a bobbin. Especially the bobbin case is fitted and removed every time when the lower thread is used up or other cases, and accordingly it is very advantageous to easily perform all of these operations.

. Another object is to maintain the raised position of the finger piece with a simple construction. Concerning the maintaining of the standing state, it has been proposed to provide a special member on the bed in order to maintain the finger piece in the raised position, however such a structure is very complicated and requires not only arrangements of fairly high cost members but also special treatmentsson the bed, and the working members often catch the cloth or thread around the rotary shuttle. The device of the present invention is of simple construction andmay be easily applicable for the usual prior bobbin.

Another important object is to simplify the manufacturing and assembly operations and to provide a bobbin case, for which the above mentioned stopping screw to be equipped in the sliding piece is no longer required.

The structures as well as the operation of the invention will become apparent with reference to the attaching drawings, in which,

FIG. 1 is a cross-sectional view showing a standing state of the finger piece on the bobbin case according to the invention in raised position;

FIG. 2 is a cross-sectional view showing the finger piece in position abutting against the bobbin case;

FIG. 3 is a front view of the bobbin case of the invention;

FIG. 4 is an oblique view showing the finger piece;

FIG. 5 is a perspective exploded view of the bobbin case;

FIG. 6. is an enlarged partial view of the head part of the finger piece shown in FIG. 1;

FIG. 7 is an enlarged partial view showing the finger piece in the position of FIG. 2;

FIG. 8 is a cross-sectional view of an embodiment of the invention showing the finger piece at right angle to the bobbin front face;

FIG. 9 is an enlarged view of the head portion of the finger piece in the position of FIG. 8;

FIG. 10 is a cross-sectional view of another embodiment according to the present invention FIG. 11 is an enlarged partial view of the head portion of the above;

FIG. 12 is an enlarged partial view similar to FIG. 11 and showing the finger piece in raised position;

FIG. 13 an oblique view of the rear side of another embodiment of a finger piece according to the present invention;

FIG. 14 is an enlarged view of the head portion of the finger piece of FIG. 13 in raised position;

FIG. 15 is a view similar to FIG. 14 with the finger piece in abuttingposition; and

FIG. 16 is an enlarged plan view of the hole in the bobbin case.

To explain the invention with these drawings; A case body 1 forming a bobbin compartment 18 therein is provided with a tubular shaft 2 in its central part, and a bobbin shaft 6 shown in FIG. 1 in imaginary lines is fitted in the bore 16 of the tubular shaft. A concave groove 10 is formed in the front wall of this case body 1 as shown in FIG. 3, and guide grooves 11 11 are provided in opposite side face which define the groove. Edge portions 35 35 of a sliding member 3 are mounted respectively in the grooves 11 11 so that the member 3 may be moved to the right and left as viewed in FIG. 3, and a spring receiving portion 12 is provided adjacent to one groove 11 arranged within portion 12 is a spring 9 whose end portion abuts against a projection 31 projecting laterally from said sliding member 3. A first and second apertures 13 and 14 are spaced from each other formed in the bottom wall of the groove 10. A pair of laterally spaced bearings 38 are formed on one end portion of the above mentioned sliding member 3, and a pivoting part 8 of a finger piece 4 is located between and connected to bearings 38 38 by means of a pivot pin 34. The pivoting part 8 is formed with a cam portion 83 which is fitted in the first aperture 13 when the finger piece 4 is leveled as shown in FIG. 2 and which is so formed that the sliding member 3 and this finger piece 4 can not slipped out of the groove to the left sideas viewed in FIG. 2 by the elastic force of said spring 9. The other end of the sliding member 3 forms a fitting portion 32 which is bent inwards to be engaged with and released from the end portion of a bobbin 5, and this fitting portion 32 is located in the second aperature l4 and accordingly this second aperature 14 is cut so deeply to the side wall of the bobbin body 1 as to fully receive such a fitting portion 32. A stopping screw 37 projecting into said second aperature 14 is connected to the rear side of the sliding member 3, and this stopping screw 37 limits the sliding, to the right as viewed FIGS. l-3, of said sliding member 3 against the elastic force of the spring 9. The position of such a stopping screw 37 is chosen so that a stepped portion 85 of the finger piece 4 so that the screw 37 and the engaging part 82 of the finger piece will engage adjacent end faces of the apertures 13 and 14 when the finger piece 4 is in the raised position, that is, the distance between the side of the stopping screw 37 and an engaging part 82 is almost the same as the distance between the inner sides of the apertures l3 14. The above sliding member 3 is formed with a hole 36 in its center, and when said piece 3 is moved to the left by the elastic force of the spring 9 as shown in FIG. 2, the face portion 36a is stopped at a neck part 6a of a bobbin shaft 6 in inserted in the bore 16 as shown in FIG. 1 so that the bobbin case can not be withdrawn from said bobbin shaft, but when the member 3 is moved to the position as shown in FIG. 1 the engagement with the neck part 6a is released so that the bobbin case can be withdrawn from the bobbin shaft 6, and at the same time the above mentioned fitting portion 32 prevents withdrawal of the bobbin 5 from the tubular shaft 2. Another hole 41 is provided in the center of the finger piece 4 so as to receive the head of the bobbin shaft 6 when the finger piece 4 is in the position as shown in FIG. 2, and slanted cuts 44 are formed to opposite sides of said hole 41 to receive such a head of the bobbin shaft. The finger piece 4 is formed with a grasping part 42 at the free end thereof. The configuration of the above mentioned pivoting part 8 is an important feature of the invention which is shown in FIG. 4 and which is further enlarged in FIG. 6 and FIG. 7 to illustrate its concrete configuration together with adjacent elements-in working relationship. As stated above, the pivoting part 8 is formed at its inner side with a cam portion 83 adapted to engage the rim of the first aperature 13, and is also formed with the engaging step 85 provided with two engaging faces 81 82 which extend almost at a right angle with respect to each other, and

which respectively engage with the bottom of the groove 10 of the case body 1 and the rim of the first aperture 13 when the finger piece 4 is in the raised position to maintain the same in this position.

As apparant from the above description, the sliding member 3 is subjected to the elastic force of the spring 9 shown in FIG. 3, and accordingly said sliding member 3 tends to move to the right as viewed in FIG. 6 and FIG. 7, which means that the finger piece 4 is drawn as it is to the right in FIG. 6 through the pivot 34, and if the finger piece 4 is in the position as shown in dash-dot lines in FIG. 6, the engaging face 82 is stopped at the rim of the first aperature 13. As the elastic force acts further the sliding piece 3 the finger piece 4 is turned in counterclockwise direction to the position shown in full lines in FIG. 6 and is maintained in this position by engagement of the face 81 with the bottom surface of the groove 10. It goes without saying that when the finger piece is in the raised position it is possible to insert the bobbin as shown in FIG. 1 or withdraw it from the bobbin shaft of the bobbin case. The operator can fit the bobbin to and remove it from the bobbin shaft by slightly tilting the finger piece.

When the finger piece 4 is turned in clockwise direction by operators fingers from the position shown in full linesin FIG. 6, the engaging faces 81 82 are moved to the left as viewed in FIG. 6, as a result of it the engaging face 82 is released from the rim of the first aperature 13 and the cam portion 83 engages the top edge 15 of the aperature 13, and in this way when the finger piece 4 is turned to the position shown in imaginary lines in FIG. 6 the pivot 34 is also moved forward. The further movement after the finger piece 4 is moved from the full line position to the dash-dot line position in FIG. 6 is almost automatically performed in accordance with the shape of the cain 83, which is apparant from FIG. 6, and consequently the transition to the position shown in FIG. 7

FIGS. 8 and 9 show another embodiment of the invention, and while the finger piece extends in FIGS. 1 to 7 in the raised position at an angle of 60 to to the top wall of the bobbin case, the piece 4 is maintained at right angle in FIGS. 8 and 9. As shown in FIG. 9 such a right angle position is obtained by cutting the aperature l3 deeper and expanding the cam 83 in accordance with such a deep cut. As the portion 82 of the finger piece 4 engages in the aperture 14 of the case body 1 the finger piece 4 may obtain the exact right angle, not exceeding It is very easy to grasp the finger piece in the right angle position, thereby enabling to smoothly fit and unfit to the rotary shuttle, especially preferable for the front type shuttle mechanism provided under the bed.

FIGS. 10 and the subsequent fingers show two further embodiments simplifying the manufacturing and operation of the device. FIGS. 10 to 12 show one of the further embodiment and FIGS. 13 to 16 show another embodiment. Both of them have no stopping screw as in the embodiments of FIGS. 1 to 9. As already explained, this stopping screw 37 limits the movement of the sliding piece 3 and therefore the exact setting is required, besides it causes not a few disadvantages to equip a little stopping screw 37 in the inside of a little and circular case. This is improved in the embodiments of FIGS. 10 and the subsequent figures.

In the embodiment shown in FIGS. to 12 no stopping screw 37 is used as shown in FIG. 10 the sliding piece 3 is the same as in FIGS. 1 to 7. The pivoting portion 8 of the finger piece 4 and the configurations of its elements cooperating therewith are important in the case of no stopping screw is provided, and those parts are enlarged in FIGS. 1 1 and 12. The pivoting portion 8 is formed at its innerside with a cam 83 arranged to engage the rim of the first aperature 18 when the finger piece 4 is in the position as shown in FIG. 11, and engaging faces 81 82 and 86 form a stepped portion 85. The first and second engaging faces 81 82 are, as shown in FIG. 12, respectively located in the groove 10 of the case body 1 and engaged with the upper rim. of the first aperature 13 when the finger piece 4 is in the raised position, and the third engaging face 86 engages the upper end face 16 of the aperature 13 as shown with imaginary lines in FIG. 12 when the finger piece 4 is to be rotated to the extreme position. In FIGS. 11 and 12, the aperature 13 is formed with a lateral undercut 17 so that the face 16 is formed, whereby when the face 86 engages the face 16 no portion of the finger piece extends into the case body 1.

To explain the workings in this embodiment, it is pointed out that the sliding member 13 is subjected to the force of the spring 9 as described above, and accordingly, this sliding member 3 tends to move to the left as viewed in FIGS. 11 and 12, and the raised state of the finger piece is secured with the engaging portions 81 82 and the rim of the hole 13 in the same manner as in the preceding embodiments. However, if the finger piece 4 exceeds the 90 position as shown in imaginary line in FIG. 12, then the third engaging portion 86 engages the surface 16 so that the finger piece 4 is hold at either the real and imaginary lined positions. The en gagement of the portion 86 with the surface 16 a limits the turning of the piece 4 in a clockwise direction. When the piece 4 is not thus raised excessively, the engaging relation is always maintained between the said piece 4 and the case body, and accordingly the stopping screw between the sliding piece 3 and the case body 1 is not necessary in this construction.

FIG. 13 and the following show another embodiment where the stopping screw is not used. In this connection, the pivoting portion 8 is shown in FIG. 13 in an enlarged view and FIGS. 14 and 15 show in further enlarged views the pivoting portion 8 together with the relation to the aperature l3, and FIG. 16 shows the plan view of the enlarged aperature 13, As mentioned above, this pivoting portion 8 is formed at its lower surface with a cam portion 83 to engage the rim of the first aperature 13 at downwardly turned position of the piece 4 and the engaging surface 81 and 82 include an angle of 90 with each other, and the engaging surface 81 extends laterally of and beyond the surface 82 and forms a flat part 81a, and these portions 81 82 make an engaging step 85. These surfaces 81and 82 respectively engage the bottom surface of the groove 10 of the case body 1 and the rim of the first aperture 13 when the piece 14 is in raised position as shown in FIG. 14 in order to maintain the finger piece in this position and to prevent rotation A contact of the engaging face 81a with a face 10b and that of the engaging face 82 with rim 13a limits the raising of finger piece 4.

1. a sewing machine, a combination comprising a cup-shaped bobbin case having an open end and an end wall opposite said open end, said end wall being formed with an elongated groove extending in transverse direction of said bobbin case and with a pair of apertures in said groove and extending through said end wall; a sliding member guided in said groove for reciprocation in longitudinal direction of the latter; biasing means cooperating with said sliding member for urging the latter in one direction; and a finger piece mounted in the region of one end thereof on said sliding member turnable about a pivot axis extending transverse to the direction of movement of said sliding member between a first position in which said finger piece extends substantially parallel to said sliding member and a raised position, said finger piece having an elongated gripping portion to one side of said pivot axis adapted to be gripped by the fingers of the operator and a second portion on the other side of said pivot axis and located in the region of one of said apertures, said second portion having a cam face engaging with an edge portion of said one aperture to shift said member in a direction opposite to said one direction during turning of said finger piece from said first to said raised position and a pair of engaging faces extending transverse to each other and respectively engaging the bottom face of said groove and a peripheral face defining said one aperture to thereby maintain said finger piece, when turned about said pivot axis to said raised position, in said raised position.

2. A combination as defined in claim 1 and including means for limiting turning of said finger piece from said first to said raised position to an angle of substantially 90.

3. A combination as defined in claim 2, wherein said limiting means comprise a stop member fixed to said sliding member and projecting into the other aperture.

4. A combination as defined in claim 2, wherein said end wall of said bobbin case is provided with an undercut portion extending from said one aperture in said one direction and having an abutment face facing away from the bottom face of said groove, and wherein said limiting means comprises a complementary engaging face on said second portion of said finger piece and engaging said abutment face to thereby limit turning of said finger piece.

5. A combination as defined in claim 1, wherein said engaging faces extend substantially normal to each other, and wherein one of said engaging faces is offset in direction of said pivot axis with respect to the other engaging face and wherein that engaging face which engages, after turning of said finger piece to said raised position, the bottom face of said groove extends to opposite sides of the other engaging face.

6. A combination as defined in claim 1, and including a tubular shaft coaxially fixed to said end wall of said bobbin case and extending through he interior of the latter for mounting a bobbin having a pair of flanges thereon, and wherein said sliding member has a curved end portion extending through the other of said apertures and engaging one flange of said bobbin when said sliding member is shifted in said opposite direction by said cam face of said finger piece. 

1. In a sewing machine, a combination comprising a cup-shaped bobbin case having an open end and an end wall opposite said open end, said end wall being formed with an elongated groove extending in transverse direction of said bobbin case and with a pair of apertures in said groove and extending through said end wall; a sliding member guided in said groove for reciprocation in longitudinal direction of the latter; biasing means cooperating with said sliding member for urging the latter in one direction; and a finger piece mounted in the region of one end thereof on said sliding member turnable about a pivot axis extending transverse to the direction of movement of said sliding member between a first position in which said finger piece extends substantially parallel to said sliding member and a raised position, said finger piece having an elongated gripping portion to one side of said pivot axis adapted to be gripped by the fingers of the operator and a second portion on the other side of said pivot axis and located in the region of one of said apertures, said second portion having a cam face engaging with an edge portion of said one aperture to shift said member in a direction opposite to said one direction during turning of said finger piece from said first to said raised position and a pair of engaging faces extending transverse to each other and respectively engaging the bottom face of said groove and a peripheral face defining said one aperture to thereby maintain said finger piece, when turned about said pivot axis to said raised position, in said raised position.
 2. A combination as defined in claim 1 and including means for limiting turning of said finger piece from said first to said raised position to an angle of substantially 90*.
 3. A combination as defined in claim 2, wherein said limiting means comprise a stop member fixed to said sliding member and projecting into the other aperture.
 4. A combination as defined in claim 2, wherein said end wall of said bobbin case is provided with an undercut portion extending from said one aperture in said one direction and having an abutment face facing away from the bottom face of said groove, and wherein said limiting means comprises a complementary engaging face on said second portion of said finger piece and engaging said abutment face to thereby limit turning of said finger piece.
 5. A combination as defined in claim 1, wherein said engaging faces extend substantially normal to each other, and wherein one of said engaging faces is offset in direction of said pivot axis with respect to the other engaging face and wherein that engaging face which engages, after turning of said finger piece to said raised position, the bottom face of said groove extends to opposite sides of the other engaging face.
 6. A combination as defined in claim 1, and including a tubular shaft coaxially fixed to said end wall of said bobbin case and extending through he interior of the latter for mounting a bobbin having a pair of flanges thereon, and wherein said sliding member has a curved end portion extending through the other of said apertures and engaging one flange of said bobbin when said sliding member is shifted in said opposite direction by said cam face of said finger piece. 